• 제목/요약/키워드: Modification period

검색결과 338건 처리시간 0.023초

음성 신호 시간축 변환의 실시간 구현에 관한 연구 (A Study on Real-time Implementing of Time-Scale Modification)

  • 한동철;이기승;차일환;윤대희
    • 한국음향학회지
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    • 제14권2호
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    • pp.50-61
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    • 1995
  • 본 논문에서는 음성 신호가 가지고 있는 중요한 특성을 유지하면서 발음 속도만을 변화시키는 시간축 변환 방법을 범용 디지탈 신호 처리 프로세서를 이용하여 실시간으로 구현하였다. 음성 신호 시간축 변환은 음성 신호의 발음 속도만을 변화시키기 때문에, 입력 신호와 변환 신호간의 시간적 차이가 발생하여 실시간 처리가 불가능하다. 본 논문에서는 이러한 입력, 변환 신호간의 시간차를 해결하기 위해서, 카세트 테이프 레코더의 모터 회전 속도를 조절하는 것과 같은 물리적 시간축 변환으로, 입력 음성 신호를 느리게 또는 빠르게 변환시켜 그 신호를 실시간 시스템의 입력으로 사용하였다. 카세트 레코더의 주행 속도만을 조절하는 물리적 변환은 원 신호의 피치 정보를 왜곡시켜, 원 음성의 특성을 변화시키기 때문에, 본 연구에서는 FIR 필터를 이용한 피치 보정 기법으로 왜곡된 신호를 원신호로 복원한 후, SOLA 시간축 변환 방법을 이용하여, 복원된 신호를 카세트 레코더의 모터 속도에 맞추어 시간축으로 변환하는 시스템을 실시간으로 구현하였다. 구현된 알고리듬으로 음성 신호를 시간축으로 변환하는 실험에서, 16비트 해상도를 가진 ADSP2101 프로세서로 구현한 결과와 컴퓨터 시뮬레이션 결과를 비교할 때 평균 구간 신호 대 오차비가 대략 20dB로 두 결과가 거의 유사함을 알 수 있었다.

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주의 피드백 인식 및 조절 훈련이 대학생의 주의편향 및 범불안에 미치는 효과 (Effect of Attention Feedback Awareness and Control Training on Attention Bias and Generalized Anxiety Symptoms in college students)

  • 김수정;심은정
    • 한국심리학회지:학교
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    • 제16권2호
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    • pp.207-230
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    • 2019
  • 본 연구는 범불안 성향의 대학생을 대상으로 주의편향 및 범불안 증상에 대한 주의 피드백 인식 및 조절 훈련의 효과를 확인하였다. 범불안장애 척도(GAD-7) 10점 이상 또는 펜실베니아 걱정 질문지 척도(K-PSWQ) 56점 이상이며, 주의편향을 나타내는 범불안 성향의 대학생 31명을 선발하여 주의 피드백 인식 및 조절 훈련(Attention Feedback Awareness and Control Training, A-FACT) 집단(n = 11), 주의편향수정(Attention Bias Modification, ABM) 집단(n = 10) 및 활성 위약 통제(Active Placebo Control, APC) 집단(n = 10)에 무선할당하였다. A-FACT 집단은 탐침탐사과제를 이용한 주의편향수정 훈련 시, 개인의 기저반응시간(Baseline Neutral Response time, BNR)을 기준으로 편향 여부에 대한 피드백을 실시간으로 제공받았다. ABM 집단은 기존 ABM 절차와 동일하며, APC 집단은 주의편향을 감소시키기 위한 프로그램이라는 안내는 주어지지만 피드백이 주어지지 않는 탐침탐사과제를 실시하였다. 총 8회기로 구성되어, 주 2회로 4주간 진행되었다. 주의편향수정 훈련의 효과는 주의편향점수(Attention Bias Score, ABS)와 GAD-7, K-PSWQ 및 상태 및 특성 불안 검사(K-STAI) 점수 변화로 평가하였다. 반복측정 변량분석 결과, A-FACT 집단은 ABM 집단과 APC 집단에 비해 ABS가 유의하게 감소하였으며, GAD-7, K-PSWQ 및 K-STAI 점수도 유의하게 감소하였다. 이는 주의편향수정 훈련 시 편향에 대한 피드백을 통해 편향의 여부를 인식시키고 이를 통한 주의의 자기 조절적 통제가 주의편향 및 범불안장애 증상 경감에 효과적일 가능성을 시사한다.

초음파나노표면개질기술을 이용한 저널베어링 마찰 및 피로특성 연구 (Frictional and Fatigue Characteristics of Journal Bearings by Ultrasonic Nanocrystal Surface Modification (UNSM))

  • 최갑수;다리스렝 스르멩닥와;이승철;김준형;아마노프 아웨즈한;편영식
    • Tribology and Lubricants
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    • 제31권1호
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    • pp.1-5
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    • 2015
  • In this study, we apply an ultrasonic nanocrystal surface modification (UNSM) technique to radial journal bearings (JBs) and disks made of SUJ2 and SCM440, respectively. We investigate frictional properties of untreated and UNSM-treated specimens using a ball-on-disk tester. We construct the Stribeck curve at the boundary, under mixed and full hydrodynamic lubrication conditions for the specimens using friction data obtained from JB tests. The friction at the boundary lubrication condition and the transition period to mixed lubrication condition on the UNSM-treated specimens is reduced, which improves the service life of JBs. The major effects of this reduction in the three lubrication regimes can be explained in the terms of improved mechanical properties and the presence of micro dimples. Moreover, we estimate the friction and fatigue properties of SCM440 specimens using a ball-on-disk specimen under dry and oil-lubricated conditions. Friction test results reveal that the UNSM-treated specimens show lower friction coefficient than the untreated specimens under both dry and oil-lubricated conditions. We evaluate the fatigue properties of SCM440 specimens by calculating the Hertzian stress with respect to the failure cycles. Fatigue tests results also reveal that the UNSM-treated specimens possess a longer fatigue life than the untreated specimens. The improved properties are effective in increasing the energy efficiency of bearings.

중동호흡기증후군과 지카바이러스의 대응사례분석을 통한 해외유입 신종감염병 예방시스템 구축 방안 (Developing Prevention System of Overseas Infectious Disease Based on MERS and Zika Virus Outbreak)

  • 김자영;방준석
    • 한국임상약학회지
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    • 제26권4호
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    • pp.330-340
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    • 2016
  • Objective: The outbreak of Middle East Respiratory Syndrome (MERS) started in South Korea in May 2015 and the end of crisis was declared in December 2015 by Korea Centers of Disease Control and Prevention (KCDC). However, Zika virus emerged in less than 2 months following MERS and showed higher mortality than other countries. This study is to assess the current prevention system of overseas infectious diseases, based on MERS and Zika virus outbreak and to suggest effective response system for the future. Methods: We conducted two surveys on medical specialists working at tertiary general hospitals regarding the effectiveness of responding system by KCDC against MERS and Zika virus and education in individual medical institutions using 5-Likert points. Response system was examined in three different periods as initial period, spreading period, and post disease period. Results: Although medical specialists received the notifications in initial period, no practical prevention was proven to be placed in responding stage by medical facilities (averagely 3.5/5 points in total and sub-analyses). During spreading period, there were several academic seminars conducted, which were evaluated as helpful. In post disease period, all answered that there were changes on patient treatment in all medical facilities, with mainly report system and the treatment regulations in case of suspicious patients for infection. Only 49% respondents answered positive on the possibility of initial responses. For questionnaire items regarding Zika virus, all answered that there were notifications prior to the first outbreak of the infected patient. Eighty% of respondents were aware of 'the Guideline system for traveling to dangerous areas', and answered that the system was moderately effective (averagely 3.8/5 points in total). For the effectiveness of prevention measures for foreign novel disease by KCDC, the average point was 3.0 in both of total and sub-analyses. Conclusion: There is not enough response system to prevent infectious disease in medical institutional and governmental levels in Korea. It would warrant the modification of overall medical system to improve preventive measures for initial spread of such diseases.

Elastic floor response spectra of nonlinear frame structures subjected to forward-directivity pulses of near-fault records

  • Kanee, Ali Reza Taghavee;Kani, Iradj Mahmood Zadeh;Noorzad, Assadollah
    • Earthquakes and Structures
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    • 제5권1호
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    • pp.49-65
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    • 2013
  • This article presents the statistical characteristics of elastic floor acceleration spectra that represent the peak response demand of non-structural components attached to a nonlinear supporting frame. For this purpose, a set of stiff and flexible general moment resisting frames with periods of 0.3-3.6 sec. are analyzed using forty-nine near-field strong ground motion records. Peak accelerations are derived for each single degree of freedom non-structural component, supported by the above mentioned frames, through a direct-integration time-history analysis. These accelerations are obtained by Floor Acceleration Response Spectrum (FARS) method. They are statistically analyzed in the next step to achieve a better understanding of their height-wise distributions. The factors that affect FARS values are found in the relevant state of the art. Here, they are summarized to evaluate the amplification and/or reduction of FARS values especially when the supporting structures undergo inelastic behavior. The properties of FARS values are studied in three regions: long-period, fundamental-period and short-period. Maximum elastic acceleration response of non-structural component, mounted on inelastic frames, depends on the following factors: inelasticity intensity and modal periods of supporting structure; natural period, damping ratio and location of non-structural component. The FARS values, corresponded to the modal periods of supporting structure, are strongly reduced beyond elastic domain. However, they could be amplified in the transferring period domain between the mentioned modal periods. In the next step, the amplification and/or reduction of FARS values, caused by inelastic behavior of supporting structure, are calculated. A parameter called the response acceleration reduction factor ($R_{acc}$), has been previously used for far-field earthquakes. The feasibility of extending this parameter for near-field motions is focused here, suggested repeatedly in the relevant sources. The nonlinearity of supporting structure is included in ($R_{acc}$) for better estimation of maximum non-structural component absolute acceleration demand, which is ordinarily neglected in the seismic design provisions.

아파트 건물의 구조 벽체에 대한 반응수정계수 (Investigation on Response Modification Factor of RC Structural Walls in Apartment Buildings)

  • 한상환;오영훈;이리형
    • 콘크리트학회논문집
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    • 제13권6호
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    • pp.544-552
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    • 2001
  • 우리나라의 지진위험도는 중 .약진 지역으로 분류될 수 있으며, 최근 자주 발생하지는 않지만 큰 지진(예를들면 판내부 지진)에 대하여 구조물이 저항성능을 가져야 한다는 것을 고려한다면 벽체의 성능평가는 중요하다고 할 수 있다. 본 논문의 내용은 내력벽 시스템 아파트 건물의 벽체에 대한 반응수정계수의 평가에 관한 것이다. 이를 위하여 반응수정계수에 관련한 기존 연구를 조사하여 반응수정계수의 구성요소를 분석하였다. 또한, 국내 내진기준에서 반응수정계수, 동적계수 산정의 문제점을 ATC와 UBC 기준들의 밑면전단력의 크기와 비교하여 나타내었다. 그리고, 아파트 벽체 및 전단벽에 대한 기존의 국내 .외 실험연구를 활용하여 그 구조성능을 평가하였으며, 이러한 연구내용의 결과를 기초로 허용응력도 설계용 지진하중을 규정하는 국내 내진규정의 내력벽 시스템에 대한 반응수정계수를 제안한다.

고분자 제습로터의 저온재생 성능시험 (Performance Test of Low Temperature Regeneration Polymeric Desiccant Rotor)

  • 이진교;이대영;오명도
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2009년도 하계학술발표대회 논문집
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    • pp.629-632
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    • 2009
  • The polymeric desiccant rotor is made from the super absorbent polymer by ion modification. The moisture sorption capacity of the super desiccant polymer(SDP) is 4 to 5 times larger than those of common desiccant meterials such as silica gel or zeolite. It is also known that SDP can be regenerated even at the relatively low temperature. To fabricate the desiccant rotor, firstly the SDP was laminated by coating the SDP on polyethylene sheet. Then corrugated and rolled up into a rotor. The diameter, the depth, the dimensions of the corrugated channel, etc. were pre-determined from numerical simulation on the heat and mass transfer in the desiccant rotor. The dehumidification performance was tested in a climate chamber. The relevant tests were carried out at the process air inlet temperature of $32^{\circ}C$, the regeneration air inlet temperature of $60^{\circ}C$ and the inlet dew-point temperature of both the process air and the regeneration air of $18.5^{\circ}C$, when the rotation period is long, the moisture sorption is not effective. In the desiccant rotor developed in this study, the optimum rotation period is found about 350s at the regeneration temperature of $60^{\circ}C$. It was found from further experiments that the optimum rotation tends to decreases as the regeneration temperature increases. Meanwhile, the outlet temperature of the process air deceases monotonically as the rotation period increases.

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피하지방 감량에 있어 경피침주요법의 유효성 및 안전성 평가 (The Efficacy and Safety of Ephedra and Green Tea Mesotherapy on Localized Fat)

  • 송미영;박지훈;이정호;김호준;이명종
    • 한방비만학회지
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    • 제7권1호
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    • pp.71-85
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    • 2007
  • Objectives : This study was performed to identify the efficacy and safety of ephedra and green tea mesotherapy on localized fat. Methods : Twenty-five healthy $20{\sim}35$ year overweight women (body mass $index{\geq}23kg/m^2$) were recruited and randomly assigned to two groups : experimental(mahuang and green tea) group (n=13), placebo(Normal saline) group (n=12). Total 8 times of herbarl mesotherapy treatment were performed once per week, 4 times were performed on right thigh (1st period), after wash-out for 1 week, the other 4 times were performed on left thigh (2nd period) without any modification of diet or exercise. Body composition, thigh circumferences were measured at each period before and after the intervention. Subcutaneous fat was measured by CT scan at before and after the 1st period of intervention and free fatty acid(FFA) was measured immediately before 1st intervention, 1 hour later, 24 hours later, and 7 days later. Satisfaction score and adverse events were evaluated. Results : In the subcutaneous fat, there were no significances, but in the circumferences. Experimental group had significant change when compared with placebo group (p<0.05). In FFA, experimental group has significant elevation at after 1 hour (p<0.05) evaluation. There were no serious adverse events in both groups. Conclusions : Experimental group had some significant findings in circumference, FFA, and had no serious adverse events comparing with placebo group, and no serious adverse events have been reported in both group. Mesotherapy with herb have a possibility of treating localized fat

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정익과 동익의 상호작용에 의한 비정상 천이 경계층 유동의 수치해석에 관한 연구 1

  • 강동진
    • 대한기계학회논문집B
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    • 제22권6호
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    • pp.757-770
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    • 1998
  • A Navier-Stokes code with a low Reynolds number k-.epsilon. turbulence model was tested to investigate its predictability for the unsteady transitional boundary layer flow due to rotor-stator interaction. A preliminary calculation with three different numbers of time steps 300, 600, and 1000 for a rotor wake passing period was carried out to see the effects of time steps on the unsteady flow and pressure fields due to rotor-stator interaction. Numerical solutions showed that unsteady pressure was much more sensitive to the number of time steps and over 600 time steps should be used to get a numerical solution independent of the number of time steps for a rotor wake passing period. The original low Reynolds number k-.epsilon. turbulence model showed very poor prediction of the unsteady transitional boundary layer flow due to rotor-stator interaction. This was due to the excessive production of turbulent kinetic energy near the leading edge. A modification suggested by Launder was incorporated and the modified model captured well the wake induced transitional strip. Present solutions also showed improved prediction over previous Euler/boundary layer solution in terms of the onset of unsteady transition and its extent.

중국 무용 복식을 통해 본 이국적 취향의 이입 현상에 관한 연구 - 한대부터 수당대 장수의과 우의를 중심으로 - (Research of the Exotic Fashion Observed in Chinese Dancing Costumes - From Han to Sui Tang Dynasty-)

  • 윤지원
    • 복식
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    • 제55권4호
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    • pp.124-137
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    • 2005
  • Foreign culture, introduced by cultural exchange, was modified and accepted into a new form and value system. Culture speaks for the characters of the period, so it is presented by the mutual actions of many factors affecting culture. Religion is the essence of human life and the source of ideas about life, the universe and existence, so they become hidden inside of the structure of culture. Dancing costumes present the process of cultural modification and acceptance more vividly than general costumes. This research shows that, among foreign cultures, it is Buddhism that most influenced Chinese dancing costume. Taoism was the Chinese native religion that played an oppositional role against Buddhism. Taoism was hidden in Chinese dancing costume in every age. Chinese dancing costume changed many times due to the import of exotic styles such as Buddhism that partially replaced the Taoistic tradition. Therefore, it is confirmed that the process of cultural importation of exotic style was different according to the social, historical, and cultural backgrounds of China during the period from the Han to the Sui and Tang dynasties.